#include "iostream"

using namespace std;

class POINT
{
private:
  double x, y;

public:
  void set();
  void distance();
  void show();
};



int main()
{
  POINT a, b;
  double x, y;
  cin >> x >> y;
  a.set(x, y);
  cin >> x >> y;
  b.set(x, y);

  a.show();
  cout << endl;
  b.show();
  cout << endl;
  cout << a.distance(b) << endl;
  return 0;
}